Digestive organ cancer is the most common form of malignant tumor among the Japanese. According to a survey by the Ministry of Health, Labour and Welfare, 177,000 patients die annually. Early detection and treatment can result in complete healing. The earlier the stage of the lesions, the fewer clinical symptoms are presented. Hence, some digestive organ cancer cases are detected in an advanced state, resulting in a poor prognostic outcome.
Gastric cancer is the most common form of digestive system malignant tumor among the Japanese. According to a survey by the Ministry of Health, Labour and Welfare, 50,000 patients die annually. Also, colorectal cancer is the form of digestive system malignant tumor that ranks 3rd highest number in terms of deaths due to site-specific cancer (including both males and females) among the Japanese. According to a survey by the Ministry of Health, Labour and Welfare, 41,000 patients die annually. Both gastric cancer and colorectal cancer can be cured by early detection and treatment. The earlier the stage of the lesions, the fewer clinical symptoms are presented. Hence, some cases are detected in an advanced state, resulting in a poor prognostic outcome. Opportunities for early detection include many incidental detections by endoscopic examination and/or imaging studies upon examination and many detections during investigation of symptoms that are not directly associated with cancer. Currently, no hemodiagnosis marker useful for early detection of digestive organ cancer exists. It is extremely important to establish a system capable of diagnosing the presence of digestive organ cancer at as early a stage as possible.
In particular, pancreatic cancer is a form of digestive system malignant tumor that ranks the 5th highest in terms of the number of deaths due to site-specific cancer (including both males and females) among the Japanese. According to a survey by the Ministry of Health, Labour and Welfare, 23,000 patients die annually. Cancer detection is very difficult and early cancer detection is rare. 75% of cases diagnosed with pancreatic cancer are already inoperable cases. Pancreatic cancer is a digestive organ cancer resulting in extremely poor prognosis such that the patients die within 1 to 2 years after detection (According a survey by the Center for Cancer Control and Information Services, National Cancer Center, http colon, forward slash, forward slash, gangojo, dot jp public, forward slash, cancer, forward slash, data forward slash, pancreas dot html). Although an advanced diagnostic technique for pancreatic cancer has long been desired, no useful early diagnosis method has been established.
Furthermore, biliary tract cancer is a form of malignant tumor that ranks 6th highest in terms of the number of deaths due to site-specific cancer (including both males and females) among the Japanese. According to a survey by the Ministry of Health, Labour and Welfare, 15,000 patients die annually. In most cases, early detection is difficult because of the lack of subjective symptoms.
Recent development in DNA microarray techniques and human genome sequencing have enabled extensive gene expression analysis of all genes. Accordingly, new types of cancer diagnosis, prognostic prediction, prediction of recurrence rate after treatment, and the like have become possible. The present inventors have analyzed the pathological conditions of various diseases and developed for the purpose of developing a diagnostic tool through application of gene expression analysis such as analysis of gene expression profiles in chronic hepatitis patients (see non-patent documents 1 to 3) and gene expression analysis of liver tissue in diabetes mellitus patients. However, these forms of analysis are problematic in terms of their excessive invasiveness, and hospitalization and tissue (organ tissue such as liver tissue) sampling are required. Thereafter, a method requiring less invasiveness has been reported, wherein a gene group capable of distinguishing type C cirrhosis from type C liver cancer and peripheral blood mononuclear cells are used (see patent document 1 and non-patent document 4). This method is advantageous for patients because blood is used in this method and thus it offers a low degree of invasiveness for patients. However, the method is problematic in that collection of peripheral blood mononuclear cells requires several separation processes, the method is complicated as an actual test method, and the method requires much time for the test results to be obtained.